10/24/2026
Last week I wrote up the Phocus hot folder, File > Export New Images Automatically, and spent most of the post complaining about how it's set up. I kept poking at it afterwards, because one detail stuck with me. The hot folder renders each new file with whatever adjustments that file already has, and Phocus keeps those adjustments in a .phos sidecar next to the raw. So what happens if the sidecar gets there first?
It works. Write the edits into a sidecar, drop the raw in behind it, and a TIFF comes out the other side with those edits baked in and nobody clicking anything. A feature I'd filed under "annoying" turns out to be the closest thing Phocus for Mac has to unattended batch processing. The only other batch route is Modify followed by a manual export.
I realized it could be useful for one job in particular. A lot of my frames are shot deliberately dark. At ISO 50 I underexpose to protect the highlights, and in low light I follow the rule from my ISO invariance measurements: hold shutter speed and aperture, and set ISO 200 or three stops under the meter, whichever is higher. Either way the files open dark, and I wanted Phocus to give a whole shoot a head start before it goes to Lightroom as 16-bit TIFFs.
Dark files used to slow me down earlier too, at the cull. A preview three stops under is hard to judge. Palomino, the culling app my friend Neil and I build, now takes care of that: since version 2.3.0 you can lift the exposure of the embedded JPEG preview in real time, so an intentionally underexposed frame gets judged on what it will become, not on how dark it was shot. I've written before about culling a whole Hasselblad shoot with it. The keepers still open dark in Phocus, though, and my first idea for those, a flat exposure push, turned out to be the wrong tool.
💡A note on support: This post represents my personal exploration and testing, not official technical support or guidance from Hasselblad. If you need assistance with your Hasselblad equipment, please contact Hasselblad directly: [email protected] for global support, [email protected] for the Americas, or visit hasselblad.com/support for regional options.
Key finding: Phocus for Mac reads a .phos sidecar dropped into the hot folder ahead of its raw (I've tested it on 4.2.3), so edits written into sidecars render to TIFF unattended. On deliberately dark frames, Shadow Fill 50 lifted the shadows better than a +1.5 EV push and kept the highlight headroom of an untouched render.
How a sidecar turns the hot folder into a batch processor
Phocus reads a sidecar that's already sitting in the watched folder when its raw lands, and renders the raw with it. The pairing is by filename: B0037736.3FR picks up B0037736.3FR.phos. Order matters. The sidecar goes in first, then the raw, because the raw's arrival is what starts the render.
I tested it on Phocus 4.2.3 with 30 renders. Every value came through. Phocus rewrites each sidecar as it renders, and the rewritten files still held what I'd put in.
The adjustments live in an ImageCorrection block inside the sidecar. For EV and Shadow Fill I moved each slider on its own and compared the file before and after, and each one changed exactly one key. These are the four I use:
* HighlightRecovery holds the Recovery slider, 0 to 100.
* ShadowFill holds the Shadow Fill slider as the same number you see in the panel.
* EV holds the exposure slider, but as a multiplier rather than stops. It's 2 to the power of the stops, so +1.5 is stored as 2.83, -1 as 0.5, and no change as 1.0.
* ColorTemperature set to 0 means "as shot", so each frame keeps its own white balance.
There's good news on the destination too. Last week I wrote that the folder you pick in the Export dialog doesn't stick, and said I hadn't tried exporting a file to it. I have now. Export one image manually to the folder you want. Phocus keeps it as the destination, and from then on the hot folder writes there too.
An exposure push in Phocus beats the same push in Lightroom, at first
My test set was 12 frames from one afternoon in the woods, shot on the XCD 25V at ISO 50, between 1.75 and 3.5 stops under according to the camera's meter. Each frame went through the hot folder twice, once untouched and once with +1.5 EV in the sidecar. Then I pushed the untouched TIFFs +1.5 in Lightroom Classic and compared each pair side by side.
Phocus won every pair. The shadows were much, much better, and the highlight rolloff and colour were better too. If the comparison had stopped there, this would be a post about batch-pushing exposure in Phocus.
The catch showed up when I kept editing. Raise the exposure a little further in Lightroom, which is exactly what I'd do on a real edit, and the Phocus-pushed files started blowing out almost immediately. The Lightroom-pushed versions took a lot more lift before their highlights went.
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My reading is that a TIFF can't store anything brighter than white. A push in Phocus moves the highlights up towards that ceiling and bakes them there. On one frame, B0037736, the brightest 1% of the image went from 0.73 of full scale to 0.98, and 2.4% of the pixels landed on the ceiling itself. A Lightroom push on the untouched TIFF still has the whole highlight range below white to work with, so it can keep compressing as you go.
That also explains a habit I'd had since I started handing TIFFs to Capture One: leave exposure out of Phocus. I had the rule. Now I have the reason.
A fixed push isn't predictable either. At +1.5, only one frame stayed essentially clean, and the camera's meter didn't say which one it would be. The frame 3.5 stops under clipped 0.3%. One that was only 2 stops under clipped 3.6%.
Shadow Fill lifts the shadows and leaves the headroom
So I went back to two of the frames and rendered three more versions of each: Shadow Fill 50 with exposure untouched, +1.5 EV with Recovery at 50, and a gentler +1.0 EV.
Shadow Fill won every time, and it beat the Phocus +1.5 versions on the shadows too. Then came the test that mattered. In Lightroom it took about +2 EV before the highlights blew, the same as the untouched render.
The numbers for that frame show why. These are 16-bit values scaled to 0-1, measured on the exported TIFFs:
B0037736
Darkest 1%
Median
Brightest 1%
Pixels at the ceiling
As shot (EV 0)
0.010
0.111
0.728
0.28%
EV +1.5
0.017
0.221
0.977
2.37%
Shadow Fill 50
0.022
0.174
0.732
0.28%
EV +1.5, Recovery 50
0.015
0.220
0.896
0.71%
EV +1.0
0.014
0.175
0.917
1.13%
Shadow Fill lifts the darkest tones further than the +1.5 push does, and leaves the brightest tones where they were. Recovery 50 pulls about 70% of the clipped pixels back off the ceiling, and +1.0 clips less than +1.5, but Shadow Fill beat both of them on the shadows, and neither went through the Lightroom headroom test.
This fits how Shadow Fill is built. It lifts a broad band, low midtones and shadows together, as I described in the Highlight Recovery and Shadow Fill post. On these frames it stopped short of the highlights. My sidecars use version 4 of the Exposure tool, and the same number on an older version may behave differently.
How do you apply Shadow Fill to a batch in Phocus?
Set Shadow Fill on one image, select the rest of the batch in the browser, and click Modify in the toolbar. Then export the whole selection as 16-bit TIFF. You don't need the hot folder for any of that.
The Modify dialog has a checkbox for every tool group, from White Balance down to Defringe, and every one of them starts ticked. Click Uncheck All, tick Exposure, then click Modify. Leave the defaults and Phocus copies the white balance, crop and everything else from that one image to the whole batch as well. Done right, Phocus writes the new Shadow Fill into every selected sidecar at once.
Modify copies the entire Exposure tool, so EV, Recovery and Clarity come along with Shadow Fill. Leave them at the values you want on every frame.
The hot folder removes the clicking and the waiting. Drop a batch of raws and sidecars in, walk away, and the TIFFs are there when you come back.
The script I use for this
Writing a sidecar per raw by hand isn't realistic, so I wrote a small script for my own shoots. It takes three numbers, EV, Recovery and Shadow Fill, and Recovery can also be set per frame from how much each raw clips. It writes a sidecar for every raw into the watched folder, then copies the raw in behind it, and leaves the rendering to Phocus. Frames at ISO 1600 and up go to a separate folder instead, because I run HNNR on those by hand first, and as far as I know right now, Phocus gives a script no way to start it.
Phocus can also write a second file from each export, and the hot folder honours it. Open Additional Output at the bottom of the Export dialog, pick a JPEG preset, and a JPEG lands in a Previews subfolder next to every TIFF, with the same edits in it. In my tests the hot folder only wrote JPEGs while that section was open in the dialog. The JPEG is tagged sRGB but carries no embedded colour profile.
It runs on a Mac with Phocus 4.2.3, and everything from last week's post still applies: the hot folder watches whatever folder the File Browser is showing, and it uses whatever the Export dialog holds. Once I've run it on a few more shoots, paid members who want it can email me at [email protected].
Have you seen the guide? I've published Essential Phocus 4.x for Mac - 85 topics across 8 sections and 251 pages covering everything from HNCS color science to HDR workflows. It's the reference manual Hasselblad hasn't updated since 3.8. It's $49, and updates are included.
Get it here
What I haven't tested yet
This was 12 frames from one afternoon, one lens, one kind of scene, all at ISO 50. The Shadow Fill comparison used two of them, at one value. The verdicts are my eye in Lightroom, and the numbers come from the exported TIFFs.
Your mileage will vary with how you expose. Someone who shoots a stop under will want less lift than I do at three, and I'll have to run a lot more of my own images through it, with Shadow Fill at other values and on other scenes, before the script's defaults settle.
The point is the time it saves. If Phocus is a pass-through on the way to Lightroom and the rest of your workflow is settled, the slow part is sitting in Phocus making the same change frame after frame or even just using the bulk modify, and waiting. This, for the most part, removes a lot of the need to interact with Phocus beyond setting up the watched folder and export preferences once. With the script, Phocus only has to be open and watching the folder. The script puts each sidecar and raw there, and the TIFFs come out with the edits already in them.
Write edits into .phos sidecars and the Phocus hot folder renders them to TIFF unattended. For dark frames, Shadow Fill beats an exposure push.
